In the above cited patent application Ser. No. 357,714 and the article by Shmuel J. Merhav entitled "A Nongyroscopic Inertial Measurement Unit" published May 1981 by Technion Israel Institute of Technology, a method and apparatus for measuring the specific force vector and angular rate vector of a moving body by means of a plurality of cyclically driven accelerometers is disclosed. The co-pending patent application Ser. No. 357,715 and Ser. No. 528,776 cited above disclose similar techniques for measuring the specific force vector which provide a measure of translational motion and the angular rate vector of a moving body utilizing either a single or a pair of accelerometers vibrating at a constant frequency.
For certain applications such as low cost inertial reference systems, it is desirable to minimize the complexity and the number of sensor components used in such systems. In the three axis inertial reference systems described in the above cited patent applications, it is necessary to use either three or six accelerometers vibrating or moving in three separate axes. In the mechanical systems disclosed in the patent application Ser. No. 357,715 and Ser. No. 528,776 it is necessary to provide a mechanism for driving either one or two accelerometers along three separate orthogonal axes which can require a fairly complex and expensive mechanical drive system.